jQuery: read text file from file system

问题

I am trying to read a text file using jquery, like this:

// LOAD file and split line by line and append divs
$.get('myFile.txt', function(data) {    
    var lines = data.split("\n");

    $.each(lines, function(n, elem) {
       $('#myContainer').append('<div>' + elem + '</div>');
    });
});

In chrome, I am getting:

XMLHttpRequest cannot load file:///C:/myPath/myFile.txt. Origin null is not allowed by Access-Control-Allow-Origin.

Firefox shows no error but the code is not executed (I have breakpoints in firebug and the anonymous function never runs).

Any help appreciated!

EDIT:

had to:

use the file full path
launch chrome with "--allow-file-access-from-files"

now it's working OK!

回答1:

You can't load a file from your local filesystem, like this, you need to put it on a a web server and load it from there. On the same site as you have the JavaScript loaded from.

EDIT: Looking at this thread, you can start chrome using option --allow-file-access-from-files, which would allow access to local files.

回答2:

specify the full path of the file url

回答3:

This is working fine in firefox at least.

The problem I was facing is, that I got an XML object in stead of a plain text string. Reading an xml-file from my local drive works fine (same directory as the html), so I do not see why reading a text file would be an issue.

I figured that I need to tell jquery to pass a string in stead of an XML object. Which is what I did, and it finally worked:

function readFiles()
{
    $.get('file.txt', function(data) {
        alert(data);
    }, "text");
}

Note the addition of '"text"' at the end. This tells jquery to pass the contents of 'file.txt' as a string in stead of an XML object. The alert box will show the contents of the text file. If you remove the '"text"' at the end, the alert box will say 'XML object'.

回答4:

A workaround for this I used was to include the data as a js file, that implements a function returning the raw data as a string:

html:

<!DOCTYPE html>
<html>

<head>
  <script src="script.js"></script>
  <script type="text/javascript">
    function loadData() {
      // getData() will return the string of data...
      document.getElementById('data').innerHTML = getData().replace('\n', '<br>');
    }
  </script>
</head>

<body onload='loadData()'>
  <h1>check out the data!</h1>
  <div id='data'></div>
</body>

</html>

script.js:

// function wrapper, just return the string of data (csv etc)
function getData () {
    return 'look at this line of data\n\
oh, look at this line'
}

See it in action here- http://plnkr.co/edit/EllyY7nsEjhLMIZ4clyv?p=preview The downside is you have to do some preprocessing on the file to support multilines (append each line in the string with '\n\').

回答5:

this one is working

        $.get('1.txt', function(data) {
            //var fileDom = $(data);

            var lines = data.split("\n");

            $.each(lines, function(n, elem) {
                $('#myContainer').append('<div>' + elem + '</div>');
            });
        });

回答6:

This doesn't work and it shouldn't because it would be a giant security hole.

Have a look at the new File System API. It allows you to request access to a virtual, sandboxed filesystem governed by the browser. You will have to request your user to "upload" their file into the sandboxed filesystem once, but afterwards you can work with it very elegantly.

While this definitely is the future, it is still highly experimental and only works in Google Chrome as far as CanIUse knows.

回答7:

As long as the file does not need to be dynamically generated, e.g., a simple text or html file, you can test it locally WITHOUT a web server - just use a relative path.

回答8:

If you include a file input box you can access the file as a base64 encoded string by using the FileReader object. If it's a text file a simple base64 decode will work to get the text.

Assuming the following HTML:

<input type="file" id="myfile" />

You can access using the following JQuery JS:

var file = $('#myfile').get(0).files[0];
var reader = new FileReader();
reader.onload = function (e) {
    //get the file result, split by comma to remove the prefix, then base64 decode the contents
    var decodedText = atob(e.target.result.split(',')[1]);
    //show the file contents
    alert(decoded);
};
reader.readAsDataURL(file);

回答9:

Something like this is what I use all the time. No need for any base64 decoding.

<html>
<head>
<script>
      window.onload = function(event) {
        document.getElementById('fileInput').addEventListener('change', handleFileSelect, false);
      }

      function handleFileSelect(event) {
        var fileReader = new FileReader();
        fileReader.onload = function(event) {
          $('#accessKeyField').val(event.target.result);
        }
        var file = event.target.files[0];
        fileReader.readAsText(file);
        document.getElementById('fileInput').value = null;
      }
</script>
</head>
<body>
<input type="file" id="fileInput" style="height: 20px; width: 100px;">
</body>
</html>

回答10:

You can't do this without the WEB SERVER!!! Chrome sends XMLHttpRequest to the system that looks something like this

GET /myFile.txt HTTP/1.1

And the operating system is not listening on port 80 to receive this! And even if it is, it must implement HTTP protocol to communicate with the browser...

To get this working, you must have WEB SERVER installed on your system, that will listen on port 80 and make your files available through a HTTP connection, thus making your code runnable.

来源：https://stackoverflow.com/questions/4408707/jquery-read-text-file-from-file-system

标签

jquery

file

filesystems

get